JP2000142658A - Container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the disposal as well by making pulp containing regenerated pulp and a biodegradable thickener, as major raw materials for a three- dimensional reticular structure, and forming a container using an aggregate of beads including a void inside, in the container which is used for various kinds of foods or the like, of which the upper end is open, and which comprises a body section and a bottom section. SOLUTION: As pulp containing regenerated pulp for beads which constitute this container, a virgin pulp of coniferous trees, or ground wood pulp or the like, or regenerated pulp of used papers and old magazines or the like is used. A proper amount of a solvent is added to the pulp containing regenerated pulp, and suspended and kneaded. Although not specifically limited, as the solvent, water and alcohols such as ethyl alcohol are used. Then, a biodegradable thickener is added to the mixture, and they are mixed. Then, in order to form a three- dimensional reticulate structure having a void inside, a separable foaming agent is added, and after the mixture is molded into a grain-form of a desired size, the grain is expanded. The material containing an air bubble is granulated, and dried to obtain pulp expanded beads.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container having an opening at an upper end and comprising a body and a bottom, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, plastic is often used as a material of a container having an upper end opened and having a body portion and a bottom portion, which is used for food and the like, and is formed by injection molding or the like or a container processed from a foamed polystyrene sheet. Etc., especially the latter is lightweight and has excellent heat insulation,
It was widely used in a wide range of applications.

However, when the above-mentioned plastic container is used as a disposable container or the like, there remains a problem in the processability after use. In other words, if the container is buried in the soil after use, the plastic remains in the soil because it is not degradable, and when incinerated in large quantities, the generation of high heat may damage the incinerator. Is also a concern.

[0004] On the other hand, there is a paper container as such a plastic substitute, but the heat insulation and strength are often insufficient.

In the field of cushioning materials and the like, pulp molds have attracted attention because of their ease of disposal after use, and have been increasingly used. However, this pulp mold is often manufactured using recycled pulp as a raw material, and is easy to dispose of, either by incineration or landfill.However, due to the high density, the weight increases, and the heat insulation effect is insufficient. there were.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional container, and has good incineration property and can be landfilled at the time of disposal after use. In addition, it is an object of the present invention to provide a lightweight container having an excellent heat insulating effect.

[0007]

That is, the first aspect of the present invention is as follows.
According to the invention, in a container having an upper end opened and comprising a body portion and a bottom portion, the material of the container is a pulp containing recycled pulp and a biodegradable thickener as a main raw material of a three-dimensional network structure, and a void is formed inside the container. Characterized in that it is constituted by an aggregate of beads included in the container.

Next, according to a second aspect of the present invention, in the container, a void inside the beads constituting the material of the container is
The container according to the first aspect, wherein the container is a bubble formed by a decomposition-type foaming agent.

Next, in a third aspect of the present invention, in the above-mentioned container, the voids inside the beads constituting the material of the container are:
The container according to the first aspect, wherein the container is a bubble formed by a surfactant.

Next, a fourth aspect of the present invention is the container according to any one of the first to third aspects, wherein the beads forming the material of the container are formed into an aggregate via an adhesive. A container described in Crab.

Next, a fifth invention of the present invention is characterized in that, in the container, the beads constituting the material of the container are formed into an aggregate via an adhesive layer provided in advance on the surface of the beads. A container according to any one of the first to third inventions.

[0012] Next, a sixth invention of the present invention is the fifth invention, wherein the adhesive layer previously provided on the surface of the beads constituting the container is a thermoplastic resin. Container.

Next, a seventh invention of the present invention is characterized in that, in said container, the adhesive layer previously provided on the surface of the beads constituting the container is a thermoplastic resin containing expandable particles. A container according to the fifth aspect.

Next, an eighth invention of the present invention is the fifth invention, wherein the adhesive layer provided on the surface of the beads constituting the container in advance is a water-soluble resin. Container.

Next, a ninth aspect of the present invention is the container according to any one of the first to eighth aspects, wherein a resin layer is provided on at least one surface of the container. Container.

Next, a tenth aspect of the present invention is the container according to any one of the first to eighth aspects, wherein paper is attached to at least one surface of the container. It is.

Next, an eleventh aspect of the present invention is the container according to any one of the first to eighth aspects, wherein a paper provided with a resin layer is bonded to at least one surface of the container. A container described in Crab.

Next, a twelfth invention of the present invention is the container according to any one of the first to eleventh inventions, wherein the container has a cup shape.

Next, a thirteenth invention of the present invention is the container according to any one of the first to eleventh inventions, wherein the container has a tray shape.

The fourteenth invention of the present invention is the container according to any one of the first to eleventh inventions, wherein the container has a bowl shape.

[0021]

According to the container of the present invention, since the main raw material of the container material is a pulp containing recycled pulp and a biodegradable thickening material, it is easily incinerated when the container is disposed of, and can be landfilled. Become. In addition, since the container material is composed of an aggregate of beads containing bubbles formed by a decomposable foaming agent or a surfactant inside, the container is lightweight and has an excellent heat insulating effect.

[0022]

Next, an embodiment of the container of the present invention will be described in detail. The beads constituting the container of the present invention are described in JP-A-05-271457 and JP-A-05-271457.
The present inventors have proposed in Japanese Patent Application Laid-Open No. 5-271458,
A pulp containing recycled pulp and a biodegradable thickener are used as main raw materials of a three-dimensional network structure, and are obtained by a method for producing foamed beads containing voids therein.

That is, as the pulp containing the recycled beads pulp, bleached or unbleached kraft pulp, soda pulp, sulfite pulp, groundwood pulp, ground refined wood pulp, thermomechanical pulp or the like using softwood or hardwood. Virgin pulp or recycled pulp such as waste paper, old corrugated paper, old magazines and the like can be used. Further, pulp produced in a process such as paper processing or processed into fibrous or floc by an appropriate apparatus can be used.

An appropriate amount of a solvent is added to the pulp containing the recycled pulp, and the pulp is suspended and kneaded. The solvent is not particularly limited, but is selected so that the raw material is not affected by aggregation or the like. Specifically, water and alcohols such as ethyl alcohol can be exemplified, and they may be used as a mixture.

Next, a biodegradable thickener is added and mixed. The amount of addition may be changed according to the added substance or the strength of the pulp foam buffer to be obtained later. Examples of the biodegradable thickener include sodium alginate, starch, agar, natural polysaccharides such as mannan, processed products of natural polysaccharides such as carboxymethyl cellulose, and synthetic water-soluble polymers such as polyvinyl alcohol. It is.

In order to obtain a three-dimensional network structure having voids therein, there are two methods. One is
This is a method in which a foaming agent is added, molded into granules of a desired size, and then foamed. The other is a method of adding a surfactant, stirring and foaming, and then forming into granules of a desired size.

When a blowing agent is added, the amount of addition is not limited. For 100 parts by weight of pulp, 1
It is preferable to add about 0 to 20 parts by weight, but this can be changed according to the strength. As the foaming agent, specifically, a thermal decomposition type foaming agent is preferably used, and examples thereof include inorganic foaming agents such as sodium bicarbonate and ammonium carbonate, and organic foaming agents such as azodicarbonamide and benzenesulfonyl hydrazide. After mixing with other raw materials, the mixture is molded into granules, heated, dried and foamed to obtain foamed pulp beads.

When a surfactant is added, the amount of addition is not particularly limited. 5 to 2 parts per 100 parts by weight of pulp
It is preferable to add 0 parts by weight, but this may also be changed depending on the desired degree of foaming. Examples of the surfactant include nonionic surfactants such as soap (higher fatty acid salt), Tween (trade name, manufactured by Kanto Chemical Co., Ltd.) and spun (trade name, manufactured by Kanto Chemical Co., Ltd.) Surfactants, amphoteric surfactants, anionic surfactants such as sulfonated products, and cationic surfactants can be used.

This surfactant is mixed with the above-mentioned pulp suspension, and further vigorously stirred to foam. The rate of foaming by agitation can also be adjusted as desired. The pulp foamed beads are obtained by molding the raw material containing the bubbles into granules and drying by heating.

The method of forming the beads into a container shape as an aggregate is not particularly limited. One method is to apply an adhesive to the beads by a method such as spraying, and then fill the frame into a desired container shape. Then, a method of solidifying and molding the adhesive is given. Examples of the adhesive used here include water-soluble substances such as polyvinyl alcohol, carboxymethyl cellulose, and starch, and water-dispersed adhesives such as ethylene-vinyl acetate emulsion, and solvent-based adhesives. However, there is no particular limitation.

Further, there is a method in which a coating layer is provided in advance on the bead surface, and this is used for adhesion.
Examples of the resin to be coated include a thermoplastic resin or a mixture of the thermoplastic resin and the expandable hollow particles. Examples of the resin include polyethylene resin, polyester resin, polyacrylate, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, acrylic resin, polyvinylidene chloride, polyamide such as nylon, polyvinylpyrrolidone, and the like. Examples thereof include, but are not limited to, vinyl acetate-polyethylene copolymer and polyethylene-acrylic acid copolymer. These may be used alone or as a mixture.

When the expandable particles are used in combination, a thermally expandable microcapsule in which a low boiling point solvent is sealed in the microcapsule can be used. That is, the polymer in the outer shell is softened by heating and the solvent in the inner shell is gasified, and the volume expands several tens times. Specifically, as the inner shell solvent, a heat-expandable organic resin such as isobutane, pentane, petroleum ether, and hexane is wrapped with a thermoplastic resin composed of vinylidene chloride, acrylonitrile, acrylate, methacrylate, etc. Microcapsules can be preferably used.

The mixing ratio of the expandable particles to the thermoplastic resin is not particularly limited. In coating these, those obtained by dissolving these resins in a suitable solvent including water, preparing a mixture of foamable particles in an emulsion, and the like, spraying, by a method such as spray coating, Apply and dry.

The beads prepared as described above are filled in a frame having a desired container shape, and are re-wetted or heated by an appropriate means to dissolve the adhesive, and then solidified to bind the beads together. Let it be a container.

In order to add functions such as water resistance and oil resistance to the inner and outer surfaces of the container according to the intended use of the container, a resin layer may be provided by a method such as resin film lamination or coating. It is also possible to apply a process such as laminating paper or laminating paper having a resin layer on the surface. In particular, when a resin having biodegradable properties is used, the processability is further improved.

[0036]

Next, the present invention will be described with reference to examples.
It is not limited to the materials used here.

<Example 1> Pulp: Corrugated cardboard waste paper 100 parts by weight Thickener: sodium alginate 0.5% by weight solution 2000 parts by weight Surfactant: fatty acid ester ("Tween 80" manufactured by Kanto Chemical Co., Ltd.) 5 parts by weight Part The above is vigorously stirred and foamed, then molded into a particle size of 5 mm, and immersed in a 2% calcium chloride dihydrate solution.
Sodium alginate becomes insoluble calcium alginate, which stabilizes its shape. This is 14
It was dried in an oven at 0 ° C. to obtain expanded pulp beads.

A 5% solution of carboxymethylcellulose was sprayed on the expanded pulp beads in the same amount as the weight of the beads, and then charged into a stainless steel cup container frame having an upper opening inner diameter of 96 mm, a bottom inner diameter of 86 mm, and a height of 153 mm. did. Further, a stainless steel cup container frame having a top opening outer diameter of 90 mm, a bottom outer diameter of 80 mm, and a height of 150 mm is inserted therein, and two types of frame-shaped voids,
Adjust the thickness so that the beads are filled to 3 mm, put the whole mold into an oven at 150 ° C, solidify the adhesive, dry it and bind the beads together to obtain a cup-shaped container. Was.

<Example 2> Pulp: defibrated softwood kraft pulp 100 parts by weight Thickener: polyvinyl alcohol (completely saponified, degree of polymerization: about 2400) 5% aqueous solution 1000 parts by weight Blowing agent: azodicarbonamide 20 parts by weight After the above components were mixed well to form a slurry, the mixture was molded into granules of about 4 mm, and then placed in an oven at 180 ° C., heated, foamed with a foaming agent, and further dried to obtain foamed beads.

The foamed beads were sprayed with an adhesive solution in the same manner as in Example 1, then poured into a mold, and dried by heating to obtain a cup container.

Example 3 The pulp beads obtained in Example 1 were sprayed with 100 parts by weight of a thermoplastic resin: emulsified polyethylene (Zaixen A manufactured by Sumitomo Seika Co., Ltd.) having a solid content of 25%. The spray amount was adjusted so that the solid content of the mixture was 7.5 g per liter of pulp beads. This was preliminarily dried at 80 ° C., then put into the mold used in Example 1, and adjusted so that the gap between the two types of molds was 3 mm as in the example, and then heated in a 140 ° C. oven together with the beads to form beads. The resin on the surface was softened. Thereafter, the resin was taken out of the oven and cooled, and the resin was solidified to bind the beads to obtain a cup container.

Example 4 A thermoplastic resin: emulsified polyethylene (Saixen A manufactured by Sumitomo Seika Co., Ltd.) solid content 25% solution 100 parts by weight to the pulp beads obtained in Example 1 Expandable particles: thermal expandability A mixture of 35 parts by weight of microcapsules (Microsphere F1400 manufactured by Matsumoto Yushi Co., Ltd., solid content: 70%) was sprayed. The spray amount is pulp beads 1
The mixture was adjusted so that the solid content of the mixture was 7.5 g per liter. After pre-drying this at 80 ° C.,
After adjusting the gap between the two molds to 3 mm as in the example, heating the entire mold in a 140 ° C. oven to soften the resin on the bead surface and expand the expandable particles. I let it. Then take it out of the oven and cool,
The resin was solidified and the beads were bound to obtain a cup container.

Example 5 The inner surface of a cup container obtained in the same manner as in Example 4 was spray-impregnated with wax and dried by heating to obtain a wax-coated container.

<Example 6> Polyethylene extruded from a cup base paper to a thickness of 20 microns was punched into a fan shape and a circular shape so as to have a size suitable for the inner dimensions of the cup prepared in Example 1. Then, it was attached to the cup prepared in Example 1 to obtain a cup container.

<Comparative Examples 1 and 2> As Comparative Example 1, a paper cup impregnated with wax and a container molded with polystyrene paper as Comparative Example 2 were prepared in the same shape as Examples 1 to 6, and their functions were compared. Was.

<Evaluation> An evaluation method was as follows. A bag made of a nylon / polyethylene laminated film was filled with 500 ml of hot water at 90 ° C., and this was used for the containers of Examples 1 to 6 and the eight types of containers of Comparative Examples 1 and 2. And the heat outside the container after 5 minutes was compared. The calories burned were compared, and the results were comprehensively evaluated. Table 1 shows the evaluation results.

[0047]

[Table 1]

According to the evaluation results shown in Table 1, all of the six types of containers of Examples 1 to 6 of the present invention have excellent heat insulating properties,
The calories burned were low and the processability was excellent. On the other hand, the container of Comparative Example 1 had poor heat insulating properties, and the container of Comparative Example 2 had excellent heat insulating properties, but had high burned calories.
As a comprehensive evaluation, the six types of containers of the present invention showed better results than the two types of containers of the comparative example.

[0049]

As described above, the container of the present invention is a container composed of beads made of pulp and a biodegradable thickener as main raw materials, has an easy incineration property, and has a landfill treatment. It is possible.

Further, the container of the present invention has a structure having fine voids such as air bubbles inside the constituent material, and is a lightweight and excellent heat insulating effect. Further, the density can be adjusted by adjusting the amount of the foaming agent and the thickening agent to be added, and the heat insulating effect and the strength can be given a range.

 ────────────────────────────────────────────────── ─── Continued on the front page F-term (reference) 2B260 AA02 AA20 BA04 CC02 CD30 DA01 DA18 DC04 DC05 DC09 DD02 EA11 EB02 EB08 EB09 EB11 EB19 EB42 3E033 AA08 AA10 BA10 BA13 BA15 BA17 BA19 BA21 BA24 BA25 BB04 BB08 AA4A10 4A AG51 AG59 AG64 AG97 AH29 AH34 AH36 AH37 AH48 AJ01 AJ02 AJ08 AJ10 BE08 BE14 BF08 BF09 FA16 FA19 GA05

Claims (14)

[Claims] 1. A container having an opening at the upper end and comprising a body and a bottom, wherein the container is made of pulp containing recycled pulp and a biodegradable thickener as main raw materials of a three-dimensional network structure. A container comprising an aggregate of beads contained therein. 2. The container according to claim 1, wherein the voids inside the beads constituting the material of the container are bubbles formed by a decomposable foaming agent. 3. The container according to claim 1, wherein the voids inside the beads constituting the material of the container are bubbles formed by a surfactant. 4. The container according to claim 1, wherein the beads forming the material of the container are aggregated via an adhesive. 5. The container according to claim 1, wherein the beads constituting the material of the container are aggregated via an adhesive layer provided on the surface of the beads in advance. Container. 6. The container according to claim 5, wherein the adhesive layer provided in advance on the surface of the beads constituting the container is a thermoplastic resin. 7. The container according to claim 5, wherein the adhesive layer provided on the surface of the beads constituting the container in advance is a thermoplastic resin containing expandable particles. 8. The container according to claim 5, wherein the adhesive layer previously provided on the surface of the beads constituting the container is a water-soluble resin. 9. The container according to claim 1, wherein a resin layer is provided on at least one surface of the container. 10. The container according to claim 1, wherein paper is attached to at least one surface of the container.
9. The container according to any one of claims 1 to 8. 11. The container according to claim 1, wherein a paper provided with a resin layer is attached to at least one surface of the container. 12. The container according to claim 1, wherein the container has a cup shape. 13. The container according to claim 1, wherein the container has a tray shape. 14. The container according to claim 1, wherein the container has a bowl shape.